Detector for a chromtograph

Abstract

A detector having particular utility in a gas chromotograph uses a sensor to produce signals indicative of parameters of components of a gas. A signal whose level is related to a gas parameter is generated and sent to an amplifier. The output of the amplifier is stored and a signal related to the amplifier output signal is sent by means of a feedback loop to the input of the amplifier to compensate for losses in the amplification and storage processes.

What is claimed is: 
     
       1. A gas chromotography circuit for detecting a parameter of a component of a gas, comprising: sensor means that produces signals indicative of parameters of the gas component; means connected to the sensor means for providing a signal whose level bears a relationship to the signals produced by the sensor means; means for amplifying the signal produced by the providing means; means for storing the amplified signal; and means for feeding back a portion of the stored signal into the amplifying means. 
     
     
       2. The circuit of claim 1 further including means for zeroing the signal providing means prior to the introduction of the gas to the sensor means. 
     
     
       3. The circuit of claim 1 wherein the signal feedback means includes means for preventing discharge of the storing means through the feedback means. 
     
     
       4. Circuit of claim 1 wherein the sensor means comprises a bridge network that includes temperature variable resistors. 
     
     
       5. Circuit of claim 4 wherein the signal providing means is a differential amplifier. 
     
     
       6. Circuit of claim 4 wherein the storing means is a capacitor. 
     
     
       7. In a gas chromotograph: gas sensor means that produces a signal in response to the presence of the gas; means for amplifying the signal; capacitor storage means communicating with the amplifying means; and electronic switch means having its gate connected to the capacitor storage means and its output connected to the input of the amplifier means. 
     
     
       8. A chromotograph detector circuit, comprising: bridge sensor means; means connected to the sensor means for generating a signal indicative of a parameter detected by the sensor means; an amplifier connected to the signal generating means; a capacitor connected to the output of the amplifier; a transistor connected to the output of the amplifier and the capacitor; and feedback means connected between the transistor and the input of the amplifier. 
     
     
       9. The circuit of claim 8 further including: a transistor connected across the capacitor and means for periodically switching the transistor to a conducting state. 
     
     
       10. In a gas chromotography which generates a signal that are indicative of parameters of components of a gas: an amplifier electrically communicating with the signals; a capacitor connected to the output of the amplifier; a transistor connected to the output of the amplifier and the capacitor; and a feedback loop connected between the transistor and the input of the amplifier. 
     
     
       11. The circuit of claim 9 further including: a transistor connected across the capacitor; and means for periodically switching the transistor to a conducting state.